The present invention relates to valves, more particularly to outlet valves to control the flow of liquid. It will be convenient to describe the invention in relation to outlet valves for cisterns, especially water cisterns for use in toilets although it will be appreciated that the invention may have wider application.
Environmental concerns about the excessive use of water has lead to numerous domestic practices aimed at reducing water wastage. One such practice involves the use of more water-efficient toilet flushing systems, in particular cisterns which allow the user the option of flushing using a full volume of water or a reduced volume. Building regulations differ from country to country but generally such regulations specify the particular minimum and maximum volumes of water to be used, for example a full flush of 6 liters and a half flush of 3 liters. Although the terms xe2x80x9cfull flushxe2x80x9d and xe2x80x9chalf flushxe2x80x9d are used throughout the description and claims of this specification, it will be appreciated by the skilled addressee that xe2x80x9chalf flushxe2x80x9d is not necessarily exactly half the volume of a xe2x80x9cfull flushxe2x80x9d but, for example, a full flush may equate to 9 liters and a half flush to 6 liters. The term xe2x80x9chalf flushxe2x80x9d should therefore be considered to refer to any desired reduced flushing volume.
A wide variety of dual-flush cistern outlet valves have been proposed and used. Many of these comprise apparatus for dividing the cistern into two separate reservoirs each having separate outlet valves: when a half flush is required, one of the outlet valves is opened so that one of the reservoirs empties. When a full flush is required, both valves are opened so that both reservoirs empty. These and many other dual-flush apparatus generally require two separate actuating systems to open the two valves. It is desirable to reduce the number of separately manufactured parts for a dual flush system.
It is an object of the present invention to provide a dual flush outlet valve which can be made using a minimum of separate moveable parts. It is a further object to provide a dual flush outlet valve which can be suitably adjusted to allow a variety of full and half flush volumes without the need for differently dimensioned components so that the one apparatus can be used throughout the world and adjusted easily to comply with differing regulatory requirements on flushing volumes. It is yet a further object of the present invention to provide a dual flush apparatus which utilises a pivoting or xe2x80x98flapperxe2x80x9d valve rather than a plunger valve.
Most known dual flush outlet valves also have limited scope to provide variable or extra capacity for overfilling relief from the reservoir, for example In the case of failure of the reservoir filling valve to shut-off when the reservoir has been filled to its desired level. It is an object of another aspect of the present invention to provide a dual flush outlet valve with added fixed or variable overflow protection.
In accordance with the present invention there is provided a dual volume discharge apparatus for selectively discharging a full flush or a half flush of liquid from a reservoir, said discharge apparatus including:
actuator means selectively moveable from a closed position to either a full flush position or a half flush position,
sealing means moveable by said actuator means from a closed position to either a full flush position or a half flush position, said sealing means being biased toward said closed position when in said half flush position,
liquid outlet which is sealed by said sealing means to prevent flow of liquid out of said reservoir when said sealing means is in said closed position and which allows flow of liquid out of said reservoir when said sealing means is in the full flush position or the half flush position,
stop means co-operable with said sealing means and being biased towards position capable of holding said sealing means in said half flush position when said actuator means is moved to said half flush position until a predetermined volume of liquid has been discharged from said reservoir and then allowing aid sealing means to move to said closed position thereafter.
The actuator means is selectively moveable from a closed position to either a full flush position or to a half flush position. The actuator means preferably further includes means for selecting either the half flush or full flush functions. In a preferred embodiment the actuator means includes twin selection means, a first selection means being adapted to move said actuator means from the closed position to the half flush position, and a second selection means being adapted to move the actuator means from the closed position to the full flush position. Said means may be in the form of a dual press-button device where each button when depressed causes the actuator means to move a certain distance, the two buttons each moving the actuator means a different distance. Preferably the half flush position is intermediate the closed and full flush positions and the distance the first selection means moves the actuator means when depressed by the user is less than the distance the second selection means moves the actuator means when depressed.
The actuator means moves the sealing means from a closed position to either a full flush position or to a half flush position. In a preferred embodiment the sealing means is a flapper-type valve and the actuator means acts on the sealing means to cause the sealing means to pivot between said closed, half flush and full flush positions.
The sealing means seals the liquid outlet when the actuator means is in. the closed position. When the sealing means is moved to either of the flush positions, the liquid outlet is opened and liquid in the reservoir is able to flow by gravity out of the liquid outlet.
When in the half flush position, the sealing means is biased toward the closed position. Preferably this bias is caused by the resolved static and dynamic fluid and gravitational forces acting on the sealing means when the sealing means is in the half flush position. When the sealing means has been moved from the closed position, liquid will flow out of the reservoir causing a venturi effect. This will result in a lower pressure acting on the lower surface of the sealing means and a greater pressure acting on the upper surface of the sealing means, the resultant net forces acting to urge the sealing means toward the closed position. Preferably when the sealing means is a flapper-valve, less pivotal movement of the sealing means away from the liquid outlet is required to put the sealing means in the half flush position than in the full flush position. In other words, when the actuator means is moved to the half flush position, the sealing means moves a first distance away from the liquid outlet, but when the actuator means is moved to the full flush position, the sealing means moves a further distance away from the liquid outlet.
Preferably when the sealing means is in the full flush position, the resolved forces acting upon it urge It to remain in that position, at least until the liquid level in the reservoir drops to a point where the sealing means is no longer covered with liquid. The sealing means may include a float which provides a buoyant force greater than any downward acting forces on the sealing means such that it remains in the full flush open position while there is still water in the reservoir but when the water level drops to below the float, the lack of buoyancy will cause the sealing means to close.
The apparatus further includes stop means co-operable with the sealing means. The stop means is biased towards a position capable of holding said sealing means in a half flush position when the actuator is moved to the half flush position. The stop means then holds the sealing means in the half flush position until a predetermined volume of liquid has been discharged from the reservoir. Thereafter, the sealing means moves to the closed position so that no more liquid is able to flow out of the liquid outlet. In a preferred embodiment, the stop means includes a cam which is capable of moving into a locking position when the sealing means is moved into the half flush position and there it is engaged by cooperating latching means associated with the sealing means. The stop means may move into the locking position by way of a float which biases the stop means toward the locking position when the float is providing upward buoyant forces, i.e. when there is liquid at least partially around the float. When the liquid level has dropped so that the float no longer provides upward buoyant forces the stop means may move away from the locking position so that the resultant forces acting on the sealing means cause the latter to move to the closed position and thus prevent further outflow of water from the reservoir.
In another aspect of the present invention there is provided a dual volume discharge apparatus for discharging liquid from a reservoir, said apparatus including:
a main liquid outlet communicating between said reservoir and a discharge passage,
valve means selectively moveable between a closed position where liquid is prevented from flowing out of said reservoir into said discharge passage through said main liquid outlet and an open position where liquid is able to flow out of said reservoir into a discharge passage through said main liquid outlet,
a first overflow passage having an outlet into said discharge passage and an inlet positioned at a selected fill level in said reservoir, and
at least one additional overflow passage having an outlet into said discharge passage and an inlet positioned at a selected fill level in said reservoir, such that when said valve means is in said closed position and liquid in said reservoir reaches said selected fill level liquid will flow into said overflow passages and flow into said discharge passage.
Preferably the additional overflow passage or passages are connected to the apparatus in parallel with the first overflow passage. The additional overflow passages may connect to the apparatus in a modular fashion by for example, a friction fit into an openable port in the apparatus. The additional discharge passages may have a telescopic extension sleeve allowing adjustment of the height of the inlet.
The present invention will now be described in more detail with reference to a preferred embodiment illustrated in the accompanying drawings. The description will refer to a preferred form of the invention when utilised in a toilet cistern. It is to be understood that the drawings and the following description relate to a preferred embodiment only, and are not to limit the generality of the present invention.